Possible Duplicate: How does one attack a two-time pad (i.e. one time pad with key reuse)? I recently started to follow the cryptography class of Dan Boneh on coursera.org and the first ...
In a stream cipher, the bytes of the plaintext are usually XORed with the keystream to produce the ciphertext. Would there be anything wrong with adding the bytes instead (with overflow), if adding ...
I have heard criticism of various cryptosystems saying that "at their heart, they were just XOR." Is this just ignorance, or is there something inherently wrong with XOR based ciphers?